Automatic torch ignition system for internal-combustion turbine engines



N0V 24, 1953 4 F. H. CAREY 2,660,233

AUTOMATIC TORCH IGNITION SYSTEM FOR INTERNAL-COMBUSTION TURBINE ENGINES Filed OCt. 24, 1949 /nven for FPI-06mm H. CAREN Patented Nov. 24, 1953 GINES Frederick Henry Carey, Cheltenham, England,` assgnor to Dowty Equipment Limited, Chelten ham, England Application October 24, 1949, SerialfNo. 123,147

supply of fuel tothe nozzles "of the torch igniters hasfben determined bythe setting-of an electric time-switch. f- Thus the period during'which the torch'i'gniters function has beenindependent of the {condition of {operation-` of the engine.

i The present invention seeks to provide an improved system` in 'which thewtorchigniters'will remain loperative for afperiod `dictated Vby `the condition of the engine whereby the torch -igniters' will -lnot beextinguishednuntila certain engine conditionshas `been established;` By Away of I illustration,4 vfuel may be supplied to the torch l igniter4 upon commencement of'operation ofthe f fuelsupply'lsy'stem, andwill continue to be suppliedto the' torch igniter until 'the systemcomes into full operation, whatevertime periodg'long or shortv'fmay bef required to produce this result, but almost immediately upon the Vsystems coming intofulloperation; and as anl automatic'consee quenoe thereof, theisupply of fuel to; the torch igniter is cut off, `and remains off all during normalfoperation.

':According'to the-present inventionthereis pro.`-`

videdinthe'supply duct from anengine driven pump to-the-'nozzlesof the torch igniters a'conf trolffvalve which' is sensitive to pressure from *thel supply pump so as to openand permit fuel' from the-pump to `reach said nozzles-and which is arrangedr` to "close when a predetermined pressure hasv .een `created in the supplyiline to the main f b'ur v`rs lof-*the engine.l @Such valve, hereinafter referred to as the torch-igniter 'valvefl may `con*- veniently be associatedJv with-v a "trip valve and ag circuit-*control valve. "The 'trip valve will 'open when? al predetermined `pressure has been develop'ed in'the mainburnersystemto permit fuel 'frornfthe supply-pumpl toreach the circuit con-I trolvalve and so shift the latter to `a position at which it cuts off the' supply from'the 'pumplto thet'orch ignitervalve and divertsf's'uch supply tofthermainburner 'systemf --Althoughnot es'- sential; it isl considereddesirable to'v provide be tween the' torch'igniter valve andthe nozzles of 2 the torch igniters'a small accumulator which is charged with fuel during such time as the torch igniter valve is open and'which, after the torch igniter valve closes, serves to provide for continued supply to thel torch igniters for a brief period. The invention is vapplicable to systems in which the main burners areof the direct injection type,'i. e. of the type in which all the fuel supplied to the burner passes out through its discharge orifice, ortosystems in which the main burners are of the spill type, i. e; of the type in which, except during certain operating conditions, only a proportion ofthe fuel which is supplied to 'the burner passesout through its discharge orifice and the remainder ows :back along areturnline. In order that the invention may be clearly unfderstood and readily carried into effect two sys-4 tems in accordance therewith willlnow be described by wayof example with reference to the diagrammatic drawingsV forming part ofthe specification.

Figure' 1 is a diagram of a fuel system arranged tosup'ply fuel to direct injection burners, wherein the present invention is' incorporated, and" Figure 2 is'a similar diagram, wherein the systemfsupplies fuel to Yspill'type burnersf l Referring Yto Figurel f said drawings,main l burners of the directinjection type, of which one is indicated at II, are suppliedwith fuel from 'an-engine driven pump I2 Via a throttle I3. The system comprises a booster pump I4 in a supply tankl, a circuit control valve I6, a trip diaphragm-mounted va1ve`-ll', an isolating valve I8 and torch igniter valve I9, a high-pressure 'shutoff valve 20,'an accumulator- 2|, Aand torch ig`A niters one of which is indicated at 22.

"Thevarious parts are shown in the positions they occupy when the engine is at rest,V the fuel supply pump IZin-consequence is not functioning, and'ow in the several conduits has ceased. At'starting up, the separately driven booster pump lil is first started up. Directly the pump' I2' starts 1 to turn withf the engine, the pump is off conduit I2s (assuming that cock I2C is open), and delivers by wayof conduit IiZoZY through a section of the shut-off valve 2li, and conduit 20a through 'the circuit control valve IS,'and along a conduit 23 to one endof the isolating valve I8. The pressure of th'efuel so delivered Vshifts the isolating-valve I3to the rightfagainst a spring 24 untilfth'ewvalve Iipartiallyuncovers a bleed port 25 atwhich-positicnlthe valve is maintained by the action ofthe spring'ZlI and by the escape primed by fuel-from the boosterv pump by way vof some of the uid through the port 25.

The fluid passing through the port 25 is able to flow through internal passages in the isolating valve I8 and along a branch conduit 26 leading to the line 21 extending from the burners II to the trip valve I1'. Such movement to the right of the isolating valve I8 permits the torch igniter valve I9 to unseat, said latter valve being moved by the projection 1280. on the spring loaded piston member 28. The piston member is apertured so that fuel from the conduit 23 can flow along the conduit 29 to the nozzles of the torch igniters 22. At the same time the accumulator 2l is charged through a branch line 30. While this is happening the tank booster pump I4, which is driven independently of the engine and which was previously set in motion, has, in accordance with our co-pending application Serial No. 36,011, led June 30, 1948, now Patent No. 2,640,318 issued June 2, 1953, been serving to prime the supply pump I2' and has also been feeding into the main burner supply line' 21 through conduits I.2s and 3|- and throughthe internal passages of the isolating valve I8 'and the branch conduit 26. As soon as a predetermined pressure has been built up thus in the line 21 leading to the burners II the trip valve I1Y will open and thereafter during continued operation will remain open, since the entire area ofits diaphragm is now subject to system pressure, to permit fuel to iiow along a conduit 32 to the circuit control valve I6 in order to shift saidvalve to the left against a spring 33. The valve I6 when so shifted will close the conduits 20a and 23 leading to the isolating valve I8 and to the torch igniter valve I3 both of which latter Vthereupon close. At the same time such shifting of the circuit control valve I6 places the supply pump I2 and its delivery conduit 12d in communciation with the burners II through conduits 34 and 35. Return movement of the isolating valve I8 to its closed position, as shown in Figure l, and resulting from closure of conduit 23, prevents flow from the tank booster pump reaching the branch conduit 26 from the conduit 3| so that said booster pump now serves solely for priming the supply pump I2. Closure ofthe torch igniter valve I9 to its illustrated closed position, also resulting from closureofY has been expended the torch igniters extinguish andthe system continues to function for normal 4running of the engine as dictated by the usualcontrol including the throttle I3. When the shut-off valve 20 is moved to the stopping position, i. e. is moved to the right from the positionA illustrated, the outlet-12d of the supply pu'r'npIZ communicates with the tank I5 through aconduit 36 and thelinlet of the pump I2 is placed in communication with the burners II through the branch conduit 31, as described in my'rco-pending application Serial No. 2,341, filed January 14, 194s, now Patent No. 2,530,649, is sued November 21, 1950. The pressure in the lines 3:2 andV 21 extending from the burners II to the circuit control valve I6 drops to permit the circuit control valve to return under the inuence of its spring 33 to its original position, asl'illustrated'. The conduit 32 which leads from the right-hand end of the circuit control valve I6 opens beneath the diaphragm carrying the valve element of the trip valve I1, hence the pressure in the conduit 32 brought about by the spring loading 33 is sufcient to lift or hold the valve I1 off its seat to permit escape of liquid from conduit 32 across the valve I1, into the now low-pressure conduit 21, and thus to permit the circuit control Valve I6 to return to its original position. Closing of the trip valve I1 under the influence of its biasing spring follows return of the circuit control valve I6 to its original position. The system is now ready to be .started again when desired after opening the shut-'off valve 20. It should be noted that although return to its original position of the circuit control Valve places the supply pump in communication with the previously closed conduit 23, the torch igniter valve will not unseat owing to the supply pump now being in unrestricted communication, by way of conduits I2d, 36, with the tank.

Figure 2 illustrates an arrangement in which the invention is applied to a fuel supply system incorporating thefeatures of my copending application Serial`No.'36,01l rst referred to, and of myfcopending application Serial No. 2343 filed January 141948, now Patent No. 2,608,247, issued August 26,1952, in which latter application burners known as spill burners are supplied with fuel by circulating and supply pumps. As shown, a number of spill burners, one of which is indicated at 45, each has an inlet 46 connected with the delivery side of a circulating pump 41 and a return or spill orifice 48 connected with the inlet side of said pump. The pump 41 thus serves to circulate fuel round a circuit including the swirl chambers of all the burners. During normal operation of the system a supply pump 49 withdraws fuel from a tank 50 with the assistance yof Aa booster pump 5I and, the circuit control valvef54 having been shifted to the left from the inactive position illustrated, to which itis biased by spring 66, delivers fuel through a throttle 52 by way of ducts 68, 69 to the point 53 of the circulating pump 41 at the inlet side of said circulating pump, and thence to intake 46 of the main burners. As in the Figure 1 arrangement, the system includes a circuit control valve 54, a trip valve 44, an isolating valve 38, a torch ignition valve 39 and a manually shiftable shut-off valve 55. This valve is shown occupying its left-hand position into which it 1s moved after the booster pump 5I has been set in operation and before the supply pump 49 has caused fuel to reach the burners 45 or the torch igniter nozzle 42. Before the shut-off valve had been moved to the left it served to connect the delivery side of the circulating pump 41 with the tank 50 by way of the conduit 43 and branch conduits 56 and 51. During such time as the circulating pump 41 is connected with the tank, the supply pump 49 delivers along the conduit 58 and across the non-return valve 59 into the conduit 60 connected on the one hand with -the tank 56 and on the other hand with the inlet of the supply pump. When theshut-off valve 55 has been moved into the left-hand position shown in the figure, the whole of the outputof thesupply pump 49 is directed alongv the conduit 6I to between the isolating Va1ve38 and the torch ignition'valve 39. Delivery from this pump 49 shifts the isolating valve 38 to the right to permit fuel from the conduit 6I to flow along the by-pass 62 and along the passage 63 to the conduit 64 which leads into-the conduit 43 extending in the one direction to the burners 45 and inthe other direction tothe trip valve 44. The movement of Y Dine. .PI clairrr:` i.

the u isolating' valveralso Y permits v delivery from the booster 'pump '51j to pass from the "conduit '65into lthe conduit 64 byV Wav'of 4the passage* 63. The Lbooster pumpI '5 I" vand the supplyfpurnp` 49 thereforeboth deliver to the `'inletsof the :burners'` 45.` `Thei movement vtc^ the :right ofthe isolatingvalve 3B also-*permits'fuelironr'the con yduit` 61 tolovvthrough "the torch'ignitio'nvalve (t9-along the conduit 4'! Atothe torch-igniter-noz-` zle'f-lZanol into the accumulator-"40. AiWhenlpressure'in-the delivery line 43 'reaches-va;-predeter mined pressure the trip valve "44 opensto allow fuelfrom the-line 43 to-"re'ach `the right-hand endV of "the 'circuit' control valve-541Which-latter thereby moves to the left againstfits springload'- ing-766'. f It will be-'seen that movement of the circuit control f'valve 5t tofth-'efleft vcuts off the branch line 6l fromthe boosterpumpri which novv.` serves vsolely'to prime the supply pump de. Alsothe-circuitcontrobvalvefli now permits fuel toepas's from-fthe conduitst and (i'finto 'theconduit'clead-ingat't into the closed cir;

cuity ofthe' pump- 41;@ :The l'build-upA of ypressure in'the conduit @Sand inthe conduitj v"thenf re' turns-the isolatingvalve to the positionV shown and yalso closes thetorchfignitionf valve;` The torch igniterf--nozzlef 42---continues-f' to 'receivefuel only; sovlong as theV accumulatoreil isy capableof supplying-it Iwhereafter--the' torch igniter Vis 1extinguished through flacieiof fuel supplyf The systemf-islfnow in its'nOr-maL--running condition in-which'fthe circulating pump 'il la circulates -fuel around theswirl chambers -ofthe i burners' rand the-supplypump 49 deliversintc Vthe :circulating flow at--theinlet 'side @tithe-circulating pump:l The`v main burnersdischargeY fuel tov the-extent thatY fuel is supplied f into the circuitfby the I supply`-pump and -this/isfcontrolled :fby the setting of the throttlelyz." When thev system is :to` be shut down the'shut-off valve 55 is-moved to its right-hand position sin which' thedelivery side ofthe ci-rculatingpumpflilyis -in vcornmuni'cation With-the -tank andithefoutlet` ofthe supply-pump 49 also communicatesffwith #the tank b'y-way of the non-return valvef 459.` Communicationwbeh' tween the conduits 58fand 68,V is now interrupted; 'Ihevmainuburners 45Wi1l then become extins guishedsthroughlack"ofyfuelffsupplyr r4- z-'It'will beeseen; that; in contradistin'ction tothe hitherto *employed -f arrangements; in -vvhich the durationof the' functionwof the `torch igniters-,is determined once andffor ali-bv the-setting ofthe electrically operated time switch',tlie duration i ofjoperatioiiofthe torchf'igniters' in accordance with the present invention may vary and is detered bythe-buil up" of'press'ure in the supply systernfoftli@burners -the torch igniter will not be extinguished until the main bur-r1 t. ,t avalcaliedrastabilized 60nd Wh'hfihs engine. hansb saleable 0f' l. A fuel supply system for delivery of fuel te a turbine engine of the continuous combustion type, which system comprises a torch igniter nozzic, a, supply pump adapted to be driven by such anV engine, conduit means including saidpump and said nozzle, and including a portion adapted to be connected to a fuel source for supply of fuel tosaid pump, and also adapted to be connected by a normal running path to a main burner noz-y zle of such an engine'but not to said torch igniter nozzle; a manually shiftable shut-oit valve and a pressure-shiftable circuit control valve connected in such normal runningpath suc.V

cessivelyfrom said hpun-1p to 0the"burner'conne'c-S tion, and each having passages forinclusion in suchv normal running'path and each `shiftab'le'to open or-to 'close the normal running path, and conversely tocloseor to open an alternate'path, said 4#conduit means including another portion constituting `such alternate path,"betwen said pumparid each of the `rnain-burner nozzle con`` nection and said torch igniter nozzle, fthe shutoif valve :and the circuit'control valve having alsogna'ssagesf for' inclusion, inaccordanceY with their respective shifted positions,iin the valter nate path;y a torch'i'gniter valve means in the al ternate path,vbetween the circuit control valve and the torch igniternozzle, said torchigniter valve means being biased to closenormally, but operable under the inuence of pressure in the alternate path while the normalIpathris closed; to be'opened thereby; and said conduit means including av pressurel connection' to saidfci'rcuit control l valve, and'l subject to' systempressure; as delivered-itc the main burnernozzle'ccnnection by :either path, toshift' said-circuitcontrol valve automatically under the influence' of suohrs'y's`A tem pressure intoposition to open the normal running path and to close the alternatepath, and so to terminatev automatically the `fuel sup?- ply to, the' torchv igniter-nozzle upon lattainment of 'supply under adequate pressurei'to the main burnervnozzle connection.` f

2. A fuelsupply system as; defined; in iclaimil; including' additionally an;accumulatorfirr Vthe alternate pathv between-ltheftorchrigniter valve and the -torch igniter nozzle, for; limited further supplyrtov the latter following closure/of the :for-'- mel.., N, u" hm Y fn www s:

3. ALfuel supply-system,aspdeiined in'clai including a selfclosing tripvalvevarranged in the,` pressure connection-v to` the circuit; control valve to prevent -accessfofl subnormals'isystem pressureto the circuit'control valve; and thus to retain the latter in position tozclose off .the normal vpath,` when itself clcsed',:but subject 'to system pressure andA arranged toppen, fornace,

cess ofsystem pressure:` tothef circuit; control valvetov shift the latter into positionto'open the normal path, .upon l,attainmentof-.apredeter mined `system pressure consonant =ivvith-znormal burner ,nozzle operation.,y my# l 4. A ffuel supply system' for theasupply offuel toa turbine engine of the-continuouscombustion` type,- which 'system' includes a main burnernozzle,V agftorch igniter -nczzle,-a-supply pump means adapted to be driven by` such :an engine `and conduit means interconnecting said main .burner nozzle, said torchignitennozzle, and said-V supply pump means; `said conduitmeans including alsoy an'intake duct for-connectingthe-intake, of said pu A s means 1Vtoafuelfsupply source, andade-` liveryduct-,leading from the ,pump means a shut- Qii1-ya,lveJ included lin ,said delivery {duct-'fand manually. shiftablevf'rom `a running positionto.

S-zcscioesmsitionz,wheremjsaicdeiivery: duct is closed, and vice versa; a pressure-shiftable main burner nozzle; a torch igniter valve means in the alternate duct, biased to close normally,

butopenable under the influence of pres-sure in the alternate duct While the normal path is closed, for delivery from the pump to the torch igniter nozzle and to the main burner nozzle; and said conduit means including a pressure connection to said circuit control valve, and subject at all times to system pressure, as delivered to the main burner nozzle by either path, to shift said circuit control valve from its biased position automatically under the influence of such system pressure into position to open the normal running path and to close the alternate duct, and so to terminate automatically the fuel supply tc the torch igniter nozzle upon attainment of supply under adequate pressure to the main burner nozzle, and at the same time to transfer supply to the main burner nozzle from the alternate duct to the normal path.

5. A fuel supply system as in claim 4, wherein the torch igniter valve means is itself biased to open, but wherein the system includes an isolating valve biased to close, and operatively connected to the torch igniter valve to hold the latter normally in closed position, said alternate duct branching at the torch igniter and isolating valves, one branch comprising said alternate duct which leads, as indicated in claim 4, past the torch igniter valve to the torch igniter nozzle, and the other branch leading past the isolating valve to said pressure connection and then to the A main burner nozzle and to the circuit control valve to shift the latter, and a trip valve interposed in said other branch, intermediate the isolating valve and the circuit control valve, to open for pressure-shifting of the circuit control valve only upon the attainment of substantially full system pressure in said pressure connection. 6. A fuel supply system as in claim 4, wherein the pump means include a circulating pump and a supply pump, and wherein the conduit means include a closed circulating duct including the circulating pump and the main burners, the systems intake duct being connected to said supply pump, and the systems delivery duct including a connection from the supply pump and beyond the circuit control valve, to said closed circulating duct, and thence to the main burners.

7. A system for the supply of fuel to a turbine engine of the continuous combustion type, which system includes a main burner nozzle, a torch igniter nozzle, a fuel tank, a high pressure supply Lpump adapted to be driven by such an engine, a

low pressurebooster pump driven independently of such an engine to deliver fuel from such fuel tank to the intake of said supply pump; a suction conduit leading from the booster pump to the supply pump; a delivery conduit leading from said supply pump to the main burner nozzle; a shutoff valve and a circuit control valve interposed successively in said delivery conduit between the supply pump and the main burner nozzle, said shut off valve being manually shiftable to open said delivery conduit for supply of fuel to the main burner nozzle for normal running and starting the engine or to close said delivery conduit to cut off fuel supply to the main burner nozzle for stopping the engine, and the circuit control valve being biased to close said delivery conduit; a branch conduit subject to delivery conduit pressure at the burner; a trip valve in said branch conduit biased to close at pressures less than full pressure therein but openable at substantially full pressure; said branch conduit leading, past said trip valve, to the circuit control valve to shift the latter under the iniluence of full delivery pressure into position to open said [delivery conduit; an alternative delivery conduit leading from the shut off valve and past the circuit control valve to said branch conduit at a point in advance of the trip valve, and arranged to be open to supply pump delivery pressure so long as the circuit control valve is in closed position; an isolating valve and a torch igniter valve operatively connected thereto and interposed in said alternative delivery conduit in advance of the trip valve and of the connection to said branch conduit, the isolating valve being biased to closed position and the torch igniter valve being biased to open position, but being held by the isolating valve in closed position; a torch igniter supply conduit leading from said torch igniter valve to the torch igniter nozzle, for supply of fuel to the latter by way of the alternative delivery conduit upon opening of the torch igniter valve; said isolating valve being sensitive to delivery pressure by way of said alternative delivery conduit to open at pressure in excess of the pressure of said booster pump, and thereby t-o permit opening of said torch igniter valve, and the trip valve being likewise sensitive to pressure past the isolating valve and the branch conduit, of a value in excess of the booster pumps pressure, to open.

8. A system as inA claim 7, including a return conduit leading from the shut off valve to the fuel tank, and arranged relative to the shut off valve for connection to the supply pumps ydelivery conduit When the shut off valve is moved to closed position, and a connecting conduit leading from the shut oi valve to the suction conduit, and arranged relative to the shut off valve for connection to the branch conduit, for return of fuel from the burner to the intake of the supply pump, and thence by way of said return conduit to the fuel tank, when the shut 01T valve is moved to closed position.

FREDERICK HENRY CAREY.

References Cited in the flle 0f this patent UNITED STATES PATENTS ...une 4...... 

